1. Field of the Invention
The present invention pertains to lifting and towing apparatus. More specifically, the present invention pertains to lifting and towing apparatus attachable to a towing vehicle and to which the front or rear wheels of a towed vehicle may be secured for lifting above the ground.
2. Description of the Prior Art
Because of the design of present day vehicles, lifting and towing apparatus for towing a disabled vehicle typically includes some type of wheel engaging apparatus to which the front or rear wheels of the towed vehicle may be secured for lifting above the ground in response to power manipulation from a towing vehicle. The towing vehicle is typically a wrecker truck or a pick-up truck which has been adapted for towing operations. In either case, the lifting and towing apparatus is typically produced by a manufacturer other than the wrecker or pick-up truck manufacturer. The apparatus is retrofitted to the wrecker or pick-up truck. Obviously, some types of lifting and towing apparatus are not suitable for one or the other. For example, many types of lifting and towing apparatus for wrecker trucks are hydraulically operated and require hydraulic components that are not suitable for use with a pick-up truck, mechanical winch devices being the preferred method of operation with pick-up trucks.
There are many types of lifting and towing apparatus and several ways of attaching them to the towing vehicle. As mentioned, some of these devices utilized with wrecker trucks are mounted above the wrecker frame either on or directly below the wrecker bed. Most of these are hydraulic units. See for example U.S. Pat. Nos. 4,634,37; 4,679,978; 4,737,066; 4,797,057; and 4,798,509.
There are other designs such as those shown in U.S. Pat. Nos. 3,951,280; 4,384,817; 4,741,661; and 4,775,285 which are suitable for mounting on the bed or the top of the frame of a pick-up truck. However, most of these are also hydraulic units and are not suitable for mechanical winch and boom construction.
There are a number of other designs which are suitable for mounting on pick-up trucks. See U.S. Pat. Nos. 4,451,193; 4,557,496; 4,573,857; and 4,632,629. Some of these are hydraulic; others are suitable for winch operation. However, in these designs, the weight of the towed vehicle is supported at the back of the truck, well to the rear of the rear axle. This creates a moment arm which tends to lift the front of the truck off of the ground. This results in instability during towing and limits the weight of the towed vehicle which can be handled therewith.
Not only do many designs have inherent operating limitations, they are also relatively expensive and not easy to attach to a towing vehicle. Most towing operators prefer a relatively inexpensive, uncomplicated and easy to operate lifting and towing apparatus. The fact that there are so many different designs, indicates a continued search for suitable apparatus.